Combustion apparatus



J. W. MILLER COMBUSTION APPARATUS May 13, 1941.

Filed Sept. -11. 1939 INVENTOR JOHN 14/ M/LLE'E Y QWY ATTORNEY.

Patented May 13, 1941 COMBUSTION APPARATUS John W. Miller, 'Lansing, Mich, assignor to Motor Wheel Corporation, Lansing, Micla, a corporation of Michigan Application September 11, 1939. Serial No. 294,250

7 Claims.

This invention relates to oil burners of the vaporizing pot type, and more particularly to a novel baflle construction for minimizing eddy currents within the'burner. V

In oil burners of the vaporizing pot type there .is a tendency for eddy currents of air, oil vapor and products of combustion to be produced within the burner and combustion chamber. These eddy currents interfere with the premixing of the fuel vapors with air in advance of combustion.

They also interfere with the proper control of the burner. Therefore, it is desirable to eliminate suchcurrents as far as possible while localizing those which do occur. If the eddy currents are confined within a small space they have little effect upon the satisfactory operation of the burner.

Itis accordingly an object-of this invention to provide a novel baflle means for vaporizin pot type burners whereby eddy currents formed within the combustion chamber and burner are localized and prevented from descending into the lower levels of the burner. Another object is to confine the eddy currents within a definite path of limited area.

Broadly the invention comprises a burner having a centrally aperture'd top wall, and a pair of vertically separated centrally apertured annular baflles within the burner. The baflles are so-constructed and arranged that the upper edge of the inner rim of the upper baflle is higher than the outer rim of the bafile, while the lower edge of the inner rim of the lower battle is lower than the outer rim of the bafile. Eddy currents formed in the upper part of the burner and combustion chamber are prevented from descending into the lower part of the burner, while eddy currents formed in the lower part of the burner are prevented from rising into the upper part, and from spreading at random within the lower'part.

The construction and operation of preferred forms of the invention willbecome more apparent in the following specification when read in embodying a modified form of the invention; and

Figure 4 is a fragmentary cross-sectional 'view taken on substantially the line 44 of Figure 3.

Referring now more specifically-to the drawing, and particularly to Figures 1 and 2, the invention is shown incorporated in a radiant heater l0. The heater comprises an outer'casing it having an upper portion l-2 constituting a combustion chamber and a lower portion [3 forming an air jacket surrounding a burner N.

' tion of the baffle.

The combustion chamber has a top wall "I, a door Hi to permit access to the interior of the burner to allow ignition of the fuel, and a iluc outlet I! connected to a chimney IS. The casing II is supported'on legs I 9 bolted thereto. The legs in this instance are metal strips, crossed at the center leaving large openings between them to permit air to enter the burner. The legs receive a threadedburner supporting screw 20. h

The burner includes a sheet metal sidewall 2| of generally frusto-conical shape and a bottom wall 22 forming an oil pan. A pipe 23 leads to any suitable source of fuel supply (not shown). and is provided with a suitable control valve 24. Directly below the fuel inlet is a depression 25 adapted to contain a small pool of oil to facilitate lighting of the fuel.

Adjacent the upper edge of the burner I4 is a top wall 26 having a large central aperture 2| therein through which air and vapors from the burner may flow to the combustion chamber. Resting on the .top wall is anantl-explosion baflie 28. v

,spaced horizontal rows' and are substantially uni formly spaced in each row.

Located above the lowermost row of air inlet openings is a lower baffle 30 having a large central aperture 3|. The ballle 30 is frusto-conical in shape and converges downwardly, whereby the lower edge of the rim of the opening is considerably lower than the outer rim of the battle.

Above the baflie 30, and preferably located high enough to include two rows of air inlet openings 29' between it and baiile 30, is an upper baille 32. This baille is shaped much the same as bailie 30 and has a large central opening 33, but converges upwardly rather than downwardly, as in the case of baflle 30.- Thus, the inner rim of baflle 32 1s v higher than its outer rim.

The apertures 3| and 33 inballles 30 and 32 are preferably somewhat smaller than the apertrue 21 in the top wall 26.

The fire produced within the apparatus just described may be varied throughout a rather wide range by simply regulating the supply of oi-l'through the medium'of the control valve 24.

Normally at low fire the oil is confined to a small pool in the depression 25 and combustion takes place immediately above the pool and below the baffle 30. Air for combustion is admitted through the bottom'row of air inlet openings 29.

Any eddy currents that'form below the baille 30 are confined there due to the downward inclina- Such eddy currents tend to roll in the direction shown by the arrows below baffle 30 and because of their limited extent to not interfere appreciably with the operation of the burner.

The warm gases issuing from the fire below the baille rise upwardly through the apertures 3|, 33 and 21 into the combustion chamber I2. The outer envelope of gas is continually cooling, particularly when it comes in contact with the side walls of the combustion chamber. These cool gases being heavier than the warmer gases in the center tend to flow downwardly as indicated by the arrows above the top wall 26, and drop into the burner. Due to the upward inclination of bailie 32, the cool gases are caught and more or less confined within the compartment of the burner between baille '32 and top wall 26, and circulate as shown by the arrows. Some of these gases may be picked up by the warmer gases issuing from the lower part of the burner and carried upward again, but they are prevented from going lower in the burner. Thus, all eddy currents forming in the apparatus are confined in such a manner that they do not interfere with the premixing of fuel vapors with the air in advance of combustion.

By suitably regulating the fuel supply the fire may be caused to move up out of the bottom compartment into the compartment between baffies 30 and 32, or into the compartment between .baflle 32 and top wall 26. In each case air for combustion is supplied by the openings 29 in the compartment in which the fire is primarily located, as well as from those in the compartments below it. When thus operating, the lower compartment or compartments become pro-mixing chambers. v

At high fire there is substantially no visible flame in the burner 14. The lower limit of the flame is at the rim of aperture 21, and the fire is located in the combustion chamber. Under such conditions it is very diflicult for eddy currents from the combustion chamber to enter the burner.

' A modified form of the invention is shown in Figures 3 and 4. Only the burner is shown as it is adapted for use in various types of heating apparatus, including a heater of the kind shown in Figures 1 and 2.

Except for the difierent shape of the baiiles, the burner of Figures 3 and 4 isidentical with that shown in Figures 1 and 2. It comprises a side wall 50 having a plurality of vertically spaced horizontal rows of air inlet openings and a bottom wall 52. The burner has a top wall 53 with a large central aperture 54. Resting on the top wall is an anti-explosion baflle 55.

Within the burner is a pair of baflles 56 and 51. The baffles 56 and 51 are flat and horizontally arranged except for a downwardly extending annular flange 58 defining a central aperture 59 in the lower baffle 5B, and an upstanding an-.

nular flange 60 outlining a central aperture in the upper baflle 51. It will be apparent that although differently shaped, the baiiles 56 and 51 have remote edges at their inner rims below and above their respective outer rims.

The efiect of the battles in the device of Figures 3 and 4 is the same as those of Figures 1 and 2, and the operation is essentially the same also. Thus, upper baffle 51 prevents eddy currents from dropping into the lower part of the burner, and lower bafile 56 confines eddy currents forming below it to the bottom of the burner.

It will be apparent from the foregoing description that the invention provides a novel means for reducing the ill efiects of eddy currents by reducing their tendency to form, while confining those that do form to as limited a zone as possible.

The scope of the invention is indicated in the appended claims.

I claim:

.1. A burner of the vaporizing pot type comprising a side wall having a plurality of vertically spaced horizontal rows of air inlet openings therein, a bottom wall, and a-pair of vertically spaced apart annular baflle plates within the burner, the upper bafiie having the upper edge of its inner rim located at a level above its outer rim and the lower bafile having the lower edge of its inner rim located at a level below its outer rim.

' 2. A burner of the vaporizing pot type comprising a side wall having a plurality of vertically spaced'horizontal rows of air inlet openings therein, a bottom wall, and a pair of vertically spaced apart annular baflrle plates within the burner, the upper bafile having the upper edge of its inner rim located at a level above its outer rim, and the lower baffle having the lower edge of its inner rim located at a level below its outer rim, said bailies being spaced apart sufliciently to include at least one row of air inlet openings between them.

3. A burner of the vaporizing pot type comprising a side wall having a plurality of vertically spaced horizontal rows of air. inlet openings therein, a bottom wall, and a pair of vertically spaced apart annular irusto-conical baiile plates within the burner, the upper bafile converging upwardly and the lower baflie converging downwardly.

4. A burner of the vaporizing pot type comprising a side wall having a plurality of vertically spaced. horizontal rows of air inlet openings therein, a bottom wall, and a pair of vertically spaced apart annular .baflle plates within the burner, the upper baflie having an upwardly extending annular flange at its inner rim and the lower baflle having a downwardly extending annular flange at its inner rim.

5. A burner of the vaporizing pot type comprising a side wall having a plurality of vertically spaced horizontal rows of air inlet openings therein, a bottom wall, a top wall for the burner having a large central aperture therein, and a pair of vertically spaced apart centrally apertured bafile plates'within the burner below the top wall, the upper edge of the inner rim of the upper baffle being at a level above that of its outer rim, and the lower edge of the inner rim of the lower baflle being at a level below that of its outer rim.

6. A burner of the vaporizing pot type comprising a side wall having a plurality of vertically and horizontally'spaced air inlet openings therein, a bottom wall, and a pair of vertically spaced apart annular baflie plates within the burner, the upper batile having the upper edge of its inner rim located at a level above its outer rim, and

. the lower baffle having the lower edge of its. inner rim located at a level below its outer rim.

7. The combination set forth in claim wherein the bafliesare spaced apart suificiently to include a plurality of the air inlet openings between them.

JOHN W. MILLER 

